Process for the production of a filter-stuff by the employment of coal or similar filter materials.



. OFFICE.

, LEONIE VON JARACZEWSKI, GEB. STERN, OF BERLIN, GERMANY.

PROCESS FOR THE PRODUCTTON OF A FILTER-STUFF BY THE EMPLOYMENT OF GOAL OB SIMILAR FILTER MATERIALS.

No Drawing.

T all whom it may concern:

Be it known that I, LfioNrn VON JARAc- ZEWSKI, ne'e STERN, a subject of the Emperor of Germany, residing ,at 8 Lennstrasse, Berlin, W., Germany, formerly Oels, have invented certain new and useful Improvements in Processes for the-Production of a Filter-Stuff by the Employment of Coal or- Similar Filter Materials, of which thefollowing is a specification.

This invention has for its object a process for producing filter material from bone black.

Hitherto filters from bone-black have been made by compressing the bone-black into slabs by air pressure. As however the fine particles of the bone-black do not bind together directly, a special binding medium was required for the manufacture of such filter slabs whereby the bone-black loses some of its considerable filtering properties.

The new process consists essentially in precipitatin bone-black in the hot Water bath on a tissue which is easily permeable and has a hairy surface. The fibers of the tissue are loosened to a certain extent in the layers of fibers have a purely mechanical effect, while the intermediate layer of bone black exerts the well known chemical or physical tered.

An example of the application of the new process is the following :A tissue having a fine hairy surface (fustian or the like) is placed in a boiling pot, the hairy side turned up, for each square meter of tissue 200 grams of water are mixed with grams of alcohol, and 30 grams of bone-black;- this mixture 1s poured on the tissue, and

boiled for 0 minutes in the closed boiling pot whereupon 1t is left to cool. The tissue Specification of Letters Patent.

. felt is produced of form and intimate action upon the liquid to be fil- I Patented July 2?, 1915.

Application filed October 6, 1913. Serial No. 793,755.

is then taken out and left to dryfor several hours without being wrung out so that it gets half dry. It is then placed between two sheets of hard glazed paper and treatedwith a hard roller heated by hot water or steam until it is perfectly dry. The tissue is then placed upon a sieve, the hairy surface and' the deposit of bone-black being turned up.

50 grams of bone-black, 15 grams of asbestos in fine flakes, 10 grams of cellulose are dissolved in one liter of water and the solution is uniformly poured on the tissue which has just been spread out. Ifthe water which flows ofi the tissue shows a yellowish color, cold water must be .poured repeatedly on the tissue to wash out the coloring matter. It will be seen at this stage already that the preliminarily boiled'tlssue does not let the bone-black pass through it.

If the water flows off quite clear the sieve with the tissue is stored in aheated room to dry rapidly and is then brought under a hours. The tissue, after having been taken out of the press, is again rolled with a heavy cold roller.

By this process there is not only obtained an absolutely secure binding of a layer of bone-black which is sufliciently finely distributed in the tissue, but also an intimatefine interlacing of the asbestos with the,hair of the filter material, whereby a filteging neness hitherto not obtainable.

A process for producing a filtering material consisting in boiling for five minutes a tissue with fine hairy surface in a solution of 50 grams of alcohol and 30 grams of bone-black, in drying said tissue, in placing the tissue on a sieve the hairy surface turned up, in uniformly pouring on the tissue a solution of 50 grams of bone-black, 15 grams of asbestos in fine flakes and '10 g ams of cellulose and in .drying'sa id tissue under pressure, substantially as described and shown and for the purpose set forth.

In testimony whereof I have affixed my signature, in presence of two witnesses.

mom. vor JARAGZEWSKI, are. STERN. 

